Field of the Invention
This invention relates to the field of delivery of programming, for example entertainment and educational programming such as that currently delivered by television and film technology. The application is a continuation-in-part of our prior application U.S. Ser. No. 08/322,069 filed Oct. 12, 1994 for a Frequency Convertor System, the contents of which are incorporated by reference.
Description of the Prior Art
In the Prior art it is known to deliver programming such as entertainment and educational programming by physical shipment of films and magnetic recording, terrestrial transmission of television signals via wires or fibers, transmission of radio frequency energy via satellite or otherwise. In particular, it is known to transmit multiple channels of television programming utilizing compressed digital or analog data over satellite and cable television systems. For all of these modes of transmission a user may typically either view the program as it is transmitted or may record a single transmitted program for later viewing. With present technology, however, it is normally required to have available one recorder for each transmitted program. Some in the prior art have attempted to develop a frequency converter system that would allow this to change with varying degrees of success.
Although some of these frequency converter systems functioned properly, many of these frequency converter systems were excessively complex and costly to manufacture. Accordingly, the frequency converter systems of the past have not found wide use in the media art.
Frequency converter systems of the prior art include U.S. Pat. No. 4,829,257 to J. Carl Cooper for an Improved Device for Accurately Phase or Frequency Shifting an Input Signal. This invention essentially incorporated a variable resistor extending between at least two known phase shifted values of the input signal. U.S. Pat. No. 4,868,428 to J. Carl Cooper discloses an Apparatus and Method for Accurately Shifting the Phase or Frequency of a Complex Signal. U.S. Pat. No. 5,097,218 to J. Carl Cooper discloses an Apparatus and Method for Accurately Multiplying the Phase or Frequency of Complex Time Varying Signals by a Given Factor Which May be Non-integer. The contents of these patents are incorporated by reference.